{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,22]],"date-time":"2026-03-22T17:52:12Z","timestamp":1774201932811,"version":"3.50.1"},"reference-count":21,"publisher":"Oxford University Press (OUP)","issue":"3","license":[{"start":{"date-parts":[[2026,3,1]],"date-time":"2026-03-01T00:00:00Z","timestamp":1772323200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/academic.oup.com\/pages\/standard-publication-reuse-rights"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2026,3,3]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Objectives<\/jats:title>\n                    <jats:p>The high-prevalence U antigen is part of the MNS blood group system and is carried on glycophorin B along with the S and s antigens. Approximately 1.5% of the Black population has U-negative or U-variant phenotypes and can potentially develop IgG antibodies against the U antigen. Anti-U antibodies are clinically significant and associated with both transfusion reactions and hemolytic disease of the fetus and newborn (HDFN).<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>A 24-year-old G4P3003 woman with a history of anti-U alloimmunization had an anti-U titer of 1:16 identified during a second-trimester antibody screen at an outside hospital. Upon repeat testing during the third trimester, the titer had increased to 1:1024. The patient was transferred to our institution for further management, where a middle cerebral artery (MCA) Doppler ultrasound was performed, revealing a normal MCA peak systolic velocity for gestational age.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>A healthy female neonate, delivered at 37\u2009weeks and 0\u2009days, had a strongly positive direct antiglobulin test with anti-U identified in the eluate. The neonate did not require phototherapy or transfusions and was discharged on day 2 of life in stable condition. A human erythrocyte antigen genotyping panel confirmed a U+ phenotype.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>This case demonstrates a passively acquired anti-U in a neonate, born to a mother with a high anti-U titer, who did not show any evidence of HDFN. To date, this is the highest anti-U maternal titer reported in the literature in which the neonate did not require any intervention.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1093\/ajcp\/aqag020","type":"journal-article","created":{"date-parts":[[2026,3,22]],"date-time":"2026-03-22T17:16:06Z","timestamp":1774199766000},"source":"Crossref","is-referenced-by-count":0,"title":["High titer anti-U in pregnancy with absent hemolysis in a U-positive neonate: a case report and literature review"],"prefix":"10.1093","volume":"165","author":[{"ORCID":"https:\/\/orcid.org\/0009-0003-3985-3262","authenticated-orcid":false,"given":"Charlotte N","family":"Nawor","sequence":"first","affiliation":[{"name":"Department of Pathology, University of Chicago , Chicago, IL,","place":["United States"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1509-2158","authenticated-orcid":false,"given":"Timothy 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